Lipid vesicles, also known as liposomes, are substantially spherical structures made of amphiphilic materials having high lipid content, such as phospholipids and surfactants. The lipids of these spherical vesicles are organized in the form of lipid bilayers e.g., multiple onion-like shells of lipid bilayers which encompass an aqueous volume between the bilayers. Paucilamellar lipid vesicles have 2-10 peripheral bilayers surrounding a large, unstructured central cavity which may be filled with water or oil soluble (hydrophobic and hydrophilic) materials.
While lipid vesicles occur naturally in cells where they are involved in intra- and inter-cellular transport, they may also be synthesized for use as model membranes. Other applications include encapsulation and delivery of cosmetic, oral, dermatological, and pharmaceutical ingredients.